1, direct lightning stroke
Direct lightning stroke contains a great deal of energy, peak voltage up to the 5000kv lightning into the ground, has great destructive power. Will result in the following three effects:
(1) rich current shed i n the number of microseconds of time, the earth potential quickly pick up high cause counterattack accident, endangering the security of persons and equipment.
(2) the lightning current to produce a strong electromagnetic wave, the induction of a high pulse voltage power lines and signal lines.
(3) of the lightning current through the electrical equipment to produce high heat, resulting in fire or explosion.
2, the conduction Ray
Distant thunder and lightning hit the line or the high voltage due to electromagnetic induction, transmitted by the outdoor power lines and communication lines to the indoor electrical equipment within the building.
3, lightning
Frequent discharge between clouds produce strong electromagnetic waves cause the common mode and differential mode interference, affect electrical equipment running.
4, the switching overvoltage
Open or disconnect the power supply system in the inductive and capacitive loads, the ends of the earth short-circuit, power supply short circuit can produce 3-5 times the normal voltage of high voltage pulse, the pulse voltage up to the power lines, can be severely damaged devices. The destructive effect of a lightning strike.
Then we turn to how to prevent the occurrence of lightning? CLP China Star Power Research Laboratory study found that in several ways is the most effective way to prevent street lamps lightning damage:
1, the external lightning protection and internal lightning protection is a combination
LED street lamps external conductor material itself the equivalent of a lightning rod in the design must be installed deflectors and ground network, these systems constitute the external lightning protection system. The system can avoid the LED street lamp of fire and personal safety accidents caused due to direct lightning stroke. Internal lightning protection system is the street lights internal ground voltage protection to protect the equipment. This system prevents overvoltage of lightning and other forms of invasive, resulting in the destruction of power, which is an external lightning protection system can not be guaranteed. Between the two complement each other, complement each other. Internal lightning protection systems in many devices, such as shell, and out of protected areas, cables, metal pipes must connect an external lightning protection system or set the overvoltage protection and equipotential bonding.
2, lightning protection and equipotential connection
Complete elimination of the destructive potential difference caused by lightning, power lines, signal lines, metal pipes, and so use overvoltage protection equipotential bonding at the interface of the inner protection zone must also be local equipotential connection, each local equipotential bonding at the interconnected, and finally connected with main and other potential.
3 , set the lightning protection zone
LED street lamps in addition to power supply, but also set some of the communications equipment used to control the lights off and the brightness of these devices and power needs to be placed in the lightning protection zones, protected areas directly affected by the shell shield. Where the electromagnetic field is much weaker.
4, high-quality protective equipment - module lightning protection and overvoltage protection modules
Mine the role of potential system protection system connected in the shortest time (nanosecond), so that the potential of the device port. Huge pulse of energy generated in the circuit due to lightning released by the short route to the earth, reducing the potential difference of the interface port of the device, and thus play the role of protective equipment. CLP Chinese satellite technology R & D team, the LED street lamp power supply module must not only be designed in accordance with the above requirements, and must undergo a rigorous inspection process.
1, with a constant voltage output function or a constant current output, or both functions of both the control device should be used GB19510.12/IEC61347-2-13 safety standards test.
2, only to control the LED light and dark, flashing, color logic changes in function of the control device should be used GB19510.12/IEC61347-2-11 safety standards test.
3, if a control device to both the above two functions, should be accordance with GB19510.12/IEC61347-2-13 safety standards test.
Practice has proved that the scientific design and rigorous testing, not only to ensure that the LED streetlight system are not subject to lightning damage, and put an end to the lightning on the power supply common mode and differential mode interference.
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